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IBO – 2008 INDIA THEORETICAL TEST – PART A _______________________________________________________________________

1

Country: ___________________

Student Code: ____________

19th INTERNATIONAL BIOLOGY OLYMPIAD

13th – 20

th July, 2008

Mumbai, INDIA

THEORETICAL TEST – PART A

Write all answers in the ANSWER SHEET.


2

Dear Participants

You have a total of 2 hours for answering Part A.

The questions in Part A have only one correct answer. Mark the correct

answer with „X‟ on the Answer Sheet, which is provided separately. The

correct way of marking the cross is shown below. Use a pen or a dark pencil

to mark your answers.

Q. NO.

a b c d e

20

The answers written in the Question Paper will not be evaluated.

Mark your answers clearly. Avoid any corrections in the Answer Sheet.

NOTE: Some of the questions may be marked “Skipped” / “Deleted”. DO NOT

attempt these questions. Also, read the question completely before

attempting it as some questions may continue from one page to the next.

The maximum number of points is 63.

Your Answer Sheets will be collected at the end of the examination.

Good Luck!!

Country: ___________________________________

First name: _________________________________

Middle name: _______________________________

Family name: ________________________________

Student Code: _______________________________


3

PART A

CELL BIOLOGY (13 points)

1. (1 point) The central dogma originally proposed by Francis Crick has seen

changes reflecting new insights obtained from time to time. Which one of the

following schematics correctly depicts our current understanding of the

replication of genetic material in various organisms and the “flow of

information” in biological systems?


4

2. (1 point) In an experiment, mice were injected intravenously with uniformly

labeled [14C] – glucose. The molecules in the body where the 14C would be

found are:

a. essential amino acids and proteins.

b. lipids and all vitamins.

c. proteins and lipids.

d. proteins and all vitamins.


5

3. (1 point) The following schematics depict the orientation of F1FO-ATPase

along with the direction of H+-transport and ATP synthesis/hydrolysis.

Of the above schematics,

a. Only I is correct.

b. Only II is correct.

c. Only III is correct.

d. Both I and III are correct.


6

4. (1 point) A given DNA sample has 60% purines. The source of this DNA is

most likely to be:

a. a eukaryotic cell.

b. a bacterial cell.

c. a bacteriophage with double-stranded DNA.

d. a bacteriophage with single-stranded DNA.


7

5. (1 point) The stage of cell division shown in the figure below represents:

a. Meiotic metaphase I with n = 4

b. Meiotic metaphase II with n = 4

c. Meiotic metaphase II with n = 8

d. Meiotic metaphase I with n = 2


8

6. (1 point) Polymerase Chain Reaction (PCR) is a technique for rapid

amplification of DNA segments. If you are given double-stranded DNA with

appropriate forward and reverse primers as shown in the figure below, the

minimum number of cycles you will require to obtain at least one copy of the

desired fragment PQ will be:

a. 1

b. 3

c. 4

d. 40

P Q

5’ 3’

3’ 5’


9

7. (1 point) Which of the primer pairs is the correct one to amplify the gene

sequence below with PCR?

5‟-GCGTTGACGGTATCAAAACGTTAT… …TTTACCTGGTGGGCTGTTCTAATC-3‟

a. 5‟-GCGTTGACGGTATCA-3‟ and 5‟-TGGGCTGTTCTAATC-3‟

b. 5‟-CGCAACTGCCATAGT-3‟ and 5‟-TGGGCTGTTCTAATC-3‟

c. 5‟-GCGTTGACGGTATCA-3‟ and 5‟-GATTAGAACAGCCCA-3‟

d. 5‟-TGATACCGTCAACGC-3‟ and 5‟-GATTAGAACAGCCCA-3‟


10

8. (1 point) Equal concentrations of urea, ethyl urea, and dimethyl urea were

separately added to a suspension of red blood cells (RBC). The relative rates

of diffusion of these molecules into RBCs will be:

a. 1 > 2 > 3

b. 1 > 2 = 3

c. 3 > 2 > 1

d. 3 = 2 > 1


11

9. (1 point) A region of a double-stranded DNA is represented in the following

schematic and the hyphens denote sequences of unspecified lengths:

The region of DNA enclosed within the box undergoes inversion. Which

one of the following correctly depicts the above DNA after inversion?


12

10. (1 point) A rare genetic disease is characterized by immuno-deficiency,

developmental and growth delay, and microcephaly. Suppose you extract

DNA from a patient with this syndrome and find almost equal quantities of

long and very short DNA strands, which enzyme is likely to be defective in

this patient?

a. DNA ligase

b. Topoisomerase

c. DNA polymerase

d. Helicase


13

11. (1 point) A scientist has suggested that a homolactic fermenting organism

grows anaerobically on glycerol 3-phosphate as the sole source of carbon,

exclusively using the following pathway:

However, the scientific community rejected this suggestion because:

a. the number of ATP molecules produced is insufficient to support growth.

b. the number of NAD+ that are reduced is not same as the number of NADH

that are oxidized in the pathway.

c. the carbon source is not as reduced as glucose and hence, cannot support

growth.

d. the number of negative charges on lactic acid (which is being produced) is not

the same as that on glycerol 3-phosphate (which is being consumed).


14

12. (1 point) The growth curve of a bacterial culture grown in a rich medium at

37°C is shown in Figure A. The same organism when exposed to 45°C for 30

min and then inoculated into a rich medium at 37°C, exhibited a growth curve

shown in Figure B.

Which of the following statements is most likely to explain the growth

pattern in Figure B?

a. Heat kills the original bacterial population and the growth pattern observed is

due to a contaminating bacterial strain.

b. Heat causes growth arrest at a particular stage, thereby synchronizing cells

and resulting in all cells dividing at the same time.

c. Heat exposure alters surface properties of cells causing errors in turbidity

measurements.

d. The increase in turbidity is not due to growth but caused by increasing lysis of

heat-treated cells with time.

Turbidity OD600

A B

Time (hours) Time (hours)


15

13. (1 point) Absorption of a drug in the gastro-intestinal tract depends on a

number of factors. Penicillin V, whose structure is shown below, is a weak

acid (pKa = 2.7). The pH in stomach is about 2.0 and that in the intestine is

7.5. Most of the drug is absorbed in the intestine.

Choose the most likely reason for this from the following statements:

a. The molecule of drug being hydrophobic in nature passes through gastric and

intestinal membranes to a very small extent. However, because of the much

greater surface area in the intestine, the major quantity of the drug is

absorbed here.

b. The un-ionized form of the drug prevails in stomach, which slows down its

absorption. Hence, the drug gets preferentially absorbed in the intestine.

c. The ionized form of the drug prevails in the intestine which hinders/slows

down its absorption. However, owing to the large surface area available in the

intestine, the drug is absorbed mainly here.

d. Due to rapid churning movement and the low pH in the stomach, the drug is

completely broken down into smaller fragments, which are subsequently

absorbed in the intestine.


16

PLANT SCIENCES (9 points)

14. (1 point) Which of the following will harm a dicotyledonous plant the most?

a. Removal of the central pith

b. Removal of the cork

c. Removal of the bark

d. Removal of the cork cambium


17

15. (1 point) The transverse sections of the leaves A and B given below

represent, respectively:

a. a xerophyte and a mesophyte.

b. a xerophyte and a floating hydrophyte.

c. a floating hydrophyte and a submerged hydrophyte.

d. a submerged hydrophyte and a xerophyte.

A B


18

16. (1 point) Certain plant species such as Red Oak (Quercus rubra) can tolerate

severe drought over a long period of time without affecting its photosynthesis.

Which of the following adaptations is likely to contribute to this ability?

a. Stomatal closure

b. Large negative leaf water potential

c. Kranz leaf anatomy

d. Fibrous root system that increases root surface area


19

17. (1 point) The net assimilation of CO2 of a plant is 0.5 moles when illuminated

during the day. The net consumption of O2 is 0.12 moles during the night.

Assuming that all the gas exchange is due to photosynthesis and respiration

of the biomass (equivalent molecular mass of 30), what is the net production

or consumption of biomass in grams during a complete 12 h day:12 h night

diurnal cycle?

a. 3.6 g/day

b. 7.8 g/day

c. 11.4 g/day

d. 15.0 g/day


20

C3

C4

0°C 25°C 40°C

1% 50% 100% Sunlight

Rate

of

ph

oto

syn

the

sis

pe

r un

it le

af

are

a

a.

C3

C4

0°C 25°C 40°C


Rate

of

ph

oto

syn

the

sis

pe

r un

it le

af

are

a

b.

0°C 25°C 40°C

C3

C4


Rate

of

ph

oto

syn

the

sis

pe

r un

it le

af

are

a

c.

C4

C3

0°C 25°C 40°C


Rate

of

ph

oto

syn

the

sis

pe

r un

it le

af

are

a

d.

18. (1 point) Choose the figure that correctly represents the photosynthetic

efficiencies of C3 and C4 plants.


21

19. (1 point) Plant chloroplasts are believed to have evolved from cyanobacteria-

like progenitors through endosymbiosis. Which of the following statements

support this hypothesis?

I. Chloroplasts and cyanobacteria share similar photosynthetic pigments and

thylakoid membranes.

II. Cyanobacteria exhibit an oxygenic photosynthesis.

III. Chloroplasts are maternally inherited.

IV. Chloroplasts have their own DNA and ribosomes.

V. Viable chloroplasts can be isolated from cells but cannot be cultured in

vitro.

VI. Prokaryotic genes express well in chloroplasts.

a. I, III, IV and V

b. I, II, IV and VI

c. I, II, III and V

d. II, IV, V and VI


22

20. (1 point) Powdery mildew is a plant disease caused by an ectoparasitic

fungus. The fungal infection can spread to neighboring host cells in the

following ways:

The ploidy levels of the structures Q, R and S are, respectively:

a. 2n, n, n

b. n, n, n

c. 2n, n, 2n

d. n, n, 2n

Hypha

Conidiophore Conidia Germination

Antheridia

Ascogonia

Plasmogamy

Karyogamy

Ascus

Ascospore

Germ tube S

R

Q


23

21. (1 point) A few characteristics of photoautotrophs are tabulated below.

Group Light compensation point

(klux units)

Light saturation point

(klux units)

CO2 compensation

point (ppm)

I 1 – 3 > 80 0

II 1 – 2 50 – 80 > 40

III 0.2 – 0.5 5 – 10 > 40

IV Data not available 1 – 2 Data not available

The four groups (I –IV) represent, respectively:

a. I: C4 plants II: Sun-loving C3 plants

III: Shade-loving C3 plants IV: Deep-sea algae

b. I: Sun-loving C3 plants II: Shade-loving C3 plants

III: C4 plants IV: Bryophytes

c. I: C4 plants II: Bryophytes

III: Sun-loving C3 plants IV: Shade-loving C3 plants

d. I: C4 plants II: Sun-loving C3 plants

III: Deep-sea algae IV: Bryophytes


24

A B C D

E

A B C D

E

22. (1 point) The stem of a lily plant was placed in water tinted with red ink to

monitor the movement of water through it. Two transverse sections of stems

are given below. In which of the labeled structures would you expect the red

color?

a. A

b. B

c. C

d. D

e. E


25

ANIMAL SCIENCES (11 points)

23. (1 point) A few intact skeletons of birds were found during a field trip to the

Pampas in Argentina. In all the skeletons examined, the sternum lacked a

keel bone. These skeletons most likely belonged to:

a. terrestrial birds capable of short and powerful flight.

b. flightless aquatic birds.

c. insectivorous flying birds.

d. flightless terrestrial birds.


26

24. (1 point) Which one of the following is a feature of a heterothermic

endotherm?

a. Its body temperature can vary, but it produces heat from its own tissues.

b. Its body temperature varies because it gains most of the heat from sources

outside its body.

c. Its body temperature does not vary because it produces heat from its own

tissues.

d. Its body temperature does not vary even though it gains heat from sources

outside its body.


27

25. (1 point) Which of the following will be an advantage of breathing in air over

breathing in water?

I. As air is less dense than water, less energy is required to move air over

respiratory surfaces.

II. Oxygen diffuses faster through air than it does through water.

III. The oxygen content of air is greater than that of an equal volume of water.

a. Only I and II

b. Only I and III

c. Only II and III

d. I, II and III


28

26. (1 point) Which characteristics would allow you to declare an organism found

on a beach as an echinoderm?

a. Radially symmetric adults with presence of spines and tube feet.

b. Radially symmetric adults with dorsal hollow notochord.

c. Exoskeleton with pharyngeal gill-slits and tube feet.

d. Radially symmetric adults with mantle cavity.


29

27. (1 point) In an individual X, the pituitary gland was found to function normally

while the adrenal glands were atrophied. In another individual Y, both the

pituitary and adrenal glands were found to be underdeveloped. If

adrenocorticotropic hormone (ACTH) is administered to these individuals as a

remedial measure, it will be effective in:

a. individual X alone.

b. individual Y alone.

c. both X and Y.

d. neither X nor Y.


30

28. (1 point) Which of the following are associated with stereoscopic vision?

I. Effect of the blind spot of one eye is cancelled by the other eye.

II. Total visual field of 360° and frontal visual field of 30°.

III. More likely to be observed in predatory birds.

IV. Centrally situated fovea that gives good visual acuity.

a. I, II and IV

b. I, II and III

c. II, III and IV

d. I, III and IV


31

29. (1 point) The glycoside “Phloridzin” present in apple peel can block the

normal reabsorption of glucose from kidney tubules. As a result, sugar is

almost completely excreted through the urine. A mouse fed with Phloridzin

along with sodium succinate will develop:

a. hypoglycemia and no sugar will be detected in the urine sample.

b. hyperglycemia and urine test for sugar will be positive.

c. hyperglycemia and no sugar will be detected in the urine sample.

d. hypoglycemia and urine test for sugar will be positive.


32

30. (1 point) Cardiac output is defined as the amount of blood pumped by each

ventricle. It is determined by multiplying the heart rate and the stroke volume.

The stroke volume is the amount of blood ejected by each ventricle with each

beat. If the heart of a woman beats 56 times in a minute, the volume of blood

in her heart is 120 ml at the end of diastole and 76 ml at the end of systole,

what would be her cardiac output?

a. 10.976 L/min

b. 2.464 L/min

c. 6.720 L/min

d. 4.256 L/min


33

31. (1 point) A population is drinking water contaminated with a modified

bisphenol-A, which is not degraded in the body. As a result, there are

measurable levels of this compound in the blood. Which of the following

would result if the modified bisphenol-A were an oestrogen-mimicking

compound?

a. Males would have decreased sperm production.

b. Males would have elevated levels of follicle-stimulating hormone.

c. Females would have elevated levels of gonadotropin-releasing hormone.

d. Males would have elevated levels of blood testosterone.

e. Follicle stimulation would increase in females.


34

32. (1 point) If a molecule of carbon dioxide released into the blood in your left

foot travels out of your nose, it must pass through all of the following

structures except the:

a. right atrium

b. pulmonary vein

c. alveolus

d. bronchus

e. pulmonary artery


35

33. (1 point) The process of artificial kidney dialysis is shown schematically using

the following symbols:

Which of the following correctly depicts the process?

a. b.

c. d.

: erythrocyte : urea

: semi-permeable membrane : salts : proteins


36

GENETICS AND EVOLUTION (17 points)

34. (1 point) A mutation results in the absence of sweat glands, a disease called

anhidrotic ectodermal dysplasia. A woman suffering from this disease has a

mosaic of skin patches lacking sweat glands. The woman is likely to be:

a. homozygous for an autosomal recessive mutation.

b. heterozygous for an autosomal dominant mutation.

c. homozygous for a X-linked recessive mutation.

d. heterozygous for a X-linked recessive mutation.


37

35. (1 point) A mink breeder allows random mating among his minks. He

discovers that, on an average, 9% of his minks have rough fur that fetches

less money when sold. So he decides to focus upon smooth fur and does not

allow minks with rough fur to mate. Rough fur is linked to an autosomal

recessive allele. What is the percentage of minks with rough fur that he will

obtain in the next generation?

a. 7.3

b. 5.3

c. 25

d. 23


38

36. (1 point) In a breed of rabbits, multiple alleles with the following dominance

relationships control coat coloration:

C (agouti) > cch (chinchilla) > ch (Himalayan) > c (albino).

An experimental cross between agouti and Himalayan produced 50% agouti

and 50% Himalayan progeny. Which of the following crosses could produce

this result?

I. Cch X chch

II. Cc X chc

III. Cch X chc

IV. Cc X chch

a. I, II and III

b. II, III and IV

c. I, III and IV

d. I, II and IV


39

37. (1 point) Alleles IA and IB present on chromosome 9 are responsible for blood

groups A and B, respectively. Blood group O results when these alleles are

either absent or not expressed. The alleles IA and IB are expressed only if the

H allele is present on chromosome 19, either in the homozygous or

heterozygous condition, where h stands for the recessive allele.

Gilbert belongs to the AB blood group. His sister Helen belongs to the A

group while their father belongs to the O group. Identify the maternal and

paternal genotypes.

Mother Father

a. H/H, IA/IB H/h, IO/IO

b. H/h, IB/IO h/h, IA/IO

c. h/h, IO/IO h/h, IA/IO

d. H/H, IA/IO H/h, IB/IO

e. h/h, IB/IO H/h, IO/IO


40

38. (1 point) The phenotypes of three experimental populations of plants are

shown in the following graphs.

The three populations X, Y and Z represent, respectively:

a. F1, F2 and F3 generations

b. P, F1 and F2 generations

c. F2, P and F1 generations

d. F3, F1 and F2 generations

Height

Rela

tiv

e f

req

uen

cy

Rela

tiv

e f

req

uen

cy

Height

Rela

tiv

e f

req

uen

cy

Height

X Y Z


41

39. (1 point) In a population of mice, 40% of males showed a dominant X-linked

trait. Assuming random mating, the most frequent mating is expected

between the genotypes:

a. XBXb and XbY

b. XBXB and XbY

c. XBXb and XBY

d. XbXb and XbY


42

40. (1 point) Hunting of Northern elephant seals reduced their population size to

as few as 20 individuals at the end of the 19th century. Their population has

since rebounded to over 30,000. But their genomes still carry the marks of

this bottleneck when compared to the population of Southern elephant seals

that was not so intensely hunted. Such bottlenecks are manifested in the form

of:

I. abundance of unique mutations.

II. increased frequency of deleterious recessive alleles.

III. reduced genetic variation.

IV. increased population size.

a. Only I and II

b. Only III

c. I, II and IV

d. II and III


43

41. (1 point) What is true for both genetic drift and natural selection?

I. They are mechanisms of evolution.

II. They are entirely random processes.

III. They result in adaptations.

IV. They affect the genetic make-up of the population.

a. I and II

b. I and III

c. II and III

d. I and IV


44

42. (1 point) The frequencies of two codominant alleles with similar fitness values

in a laboratory population of mice were 0.55 and 0.45. After 5 generations,

the values changed to 0.35 and 0.65, respectively. Which of the following

phenomena may be responsible for this observation?

I. Point mutation

II. Nonrandom mating

III. Genetic drift

IV. Selection pressure

a. I and IV

b. II and IV

c. I and III

d. II and III


45

43. (1 point) In pea plants, the allele for green color of seeds (G) is dominant

over that for yellow color (g) while the allele for round seeds (R) is dominant

over that for wrinkled seed (r). The results of an experimental cross with such

garden pea plants are tabulated below:

The parental genotypes are likely to be:

a. GgRr and Ggrr

b. Ggrr and GgRR

c. GgRr and GgRr

d. GgRR and ggRr

Seed phenotype Number

Green and round 32

Green and wrinkled 28

Yellow and round 12

Yellow and wrinkled 9


46

44. (1 point) A population has 6 times as many heterozygous as homozygous

recessive individuals. The frequency of the recessive allele will be:

a. 1/3

b. 1/4

c. 1/2

d. 1/6


47

45. (1 point) If you have data on genotypic frequencies for several generations of

a population and if you apply the Hardy-Weinberg equation to it, which of the

following can be deduced?

I. Whether evolution has occurred in the population.

II. The direction of evolution, if it has occurred.

III. The cause of evolution, if it has occurred.

a. Only I and II

b. Only I and III

c. Only II and III

d. I, II and III


48

46. (1 point) The residues of mines often contain such high concentrations of

toxic metals (e.g., copper, lead) that most plants are unable to grow on them.

However, in a particular study, certain grasses were found to spread from the

surrounding uncontaminated soil onto such waste heaps. These plants

developed resistance to the toxic metals while their ability to grow on

uncontaminated soil decreased. As grasses are wind-pollinated, breeding

between the resistant and non-resistant populations went on. But eventually,

the less resistant plants growing on contaminated soil and the more resistant

plants growing on uncontaminated soil died out. This process is indicative of:

a. mass extinction of species.

b. bottleneck effect.

c. divergent evolution.

d. disruptive selection.


49

47. (1 point) Sickle cell anemia is an autosomal recessive trait. Individual 2 in the

following pedigree is a carrier for this trait. Assuming that individuals 3 and 4

are normal homozygous, what is the probability that individual 6 will have the

disease?

a. 1/16

b. 1/32

c. 1/64

d. 1/128

: Male : Female

3

1 2

5 6

4

Aa AA


50

48. (1 point) Note the following genotypes and corresponding phenotypes:

A–B– Agouti

A–bb Albino

aaB – Black

aabb Albino

The biochemical process that can explain the above pattern is:

a.

b.

c.

d.

product of A gene product of B gene

Colorless precursor agouti pigment black pigment

product of B gene product of A gene

Colorless precursor agouti pigment black pigment

product of B gene product of A gene

Colorless precursor black pigment agouti pigment

product of B gene

Colorless precursor black pigment product of A gene agouti pigment


51

49. (1 point) In a population, 90% of the alleles at the Rh locus are „R‟. Another

alternative form of this allele is „r‟. Forty children from this population go to a

particular play school. The probability that all are Rh positive is:

a. 400.81

b. 0.9940

c. 400.75

d. 1-0.8140


52

50. (1 point) Study the pedigree and answer the following question.

The genetic relatedness between individuals 1 and 2 and between individuals

5 and 6, respectively, is:

a. 0.5 and 0.25

b. 0.25 and 0.5

c. 1.0 and 0.5

d. 1.0 and 0.25

1 2

3 4 5 6

: Dizygotic twins : Male : Female


53

ECOLOGY (7 points)

51. (1 point) A typical biomass pyramid is represented in the figure below.

If A represents a primary producer, then E is likely to be a:

a. photo-litho-heterotroph.

b. chemo-organo-heterotroph.

c. chemo-litho-autotroph.

d. photo-organo-heterotroph.

E D

C

B

A


54

52. (1 point) Comparative sensitivity of three groups of organisms to single large

doses of x-or -rays delivered at short intervals is shown in the figure below.

The three groups P, Q, R respectively are:

a. insects, mammals and bacteria

b. mammals, bacteria and insects

c. bacteria, mammals and insects

d. mammals, insects and bacteria

102 103 104 105 106

Dose in rads

P

Q

R


55

53. (1 point) Hay is boiled in water and cooled. Some pond water, containing only

heterotrophic protozoa, is added to it and kept in the dark for a long time.

Which of the following are true?

I. Heterotrophic succession of protozoa will occur with increase in total

biomass.

II. The energy of the system is maximum at the beginning.

III. Succession will occur, eventually reaching a steady state in which energy

flow is maintained.

IV. The ecosystem may undergo succession but finally all organisms will die

or go into resting stages.

a. I and III

b. II and IV

c. II and III

d. I and IV


56

54. (1 point) An ecologist is comparing the growth of a herbaceous plant species

growing in two different sites A and B. To compare the populations from the

two sites, she has harvested 30 individuals from each site, then measured the

root length, root biomass, and shoot biomass of each individual. A summary

of those measurements are as follows:

Location Mean root length

(cm)

Mean root

biomass (g)

Mean shoot

biomass (g)

Site A 27.2 + 0.2 348.7 + 0.5 680.7 + 0.1

Site B 13.4 + 0.3 322.4 + 0.6 708.9 + 0.2

Based on the data presented, which of the following statements is likely to be

true?

a. Soil water availability is lower in Site B than in Site A.

b. Plant productivity is higher in Site A than in Site B.

c. Soil water availability is lower in Site A than in Site B.

d. Soil nutrient availability is lower in Site B than in Site A.


57

55. (1 point) In an aquatic ecosystem, the total dry biomass of each of three

groups of organisms is as follows:

I. Ciliates: 1.1041 g

II. Midge larvae: 0.9845 g

III. Oligochaetes: 1.005 g

The correct food chain that they represent is:

a. I II III

b. II I III

c. I III II

d. III II I

e. II III I


58

56. (1 point) The reproductive effort of a plant is defined as the ratio of the dry

weight of its reproductive organs to that of its above-ground tissues. The

reproductive effort of two plant species M and N, as compared to their leaf

biomass is plotted in the graph below.

Choose the correct interpretation.

a. M is a r-strategist adapted to a highly disturbed habitat.

b. N is a k-strategist adapted to a highly disturbed habitat.

c. N is a r-strategist growing under favorable environmental conditions.

d. M is a k-strategist growing under favorable environmental conditions.

0.1

0

Rep

rod

uctive

eff

ort

0.1 0.5 Leaf biomass / total biomass

0.5

M

N


59

57. (1 point) Prey-predator relationships are often considered analogous to a „life-

dinner‟ relationship in behavioral ecology. Which of the following statements

best describe this analogy and the relative evolutionary rates of the prey and

predator species in a population?

I. This analogy indicates the fact that the prey species serves as the „dinner‟

for the predator species, the „life‟ of which depends on the former.

II. This analogy indicates that a prey species caught by a predator loses its

„life‟ while a predator that fails to catch a prey only loses a „dinner‟.

III. The prey species is usually under greater selection pressure from its

predators and tends to evolve faster than does a predator species.

IV. The predator species is usually under greater selection pressure because

of its dependence on a prey species for food and tends to evolve faster

than does a prey species.

a. I and III

b. I and IV

c. II and III

d. II and IV


60

ETHOLOGY (4 points)

58. (1 point) Animals can use their circadian clocks to determine direction from

the position of the sun. In a particular experiment conducted in Iceland, a bird,

kept in a cage open to the sky, was trained to seek food on the western side.

Its circadian rhythm was then phase-delayed by 6 hours and after phase

shifting, the bird was returned to its open cage at 12.00 noon real time. It was

observed to seek food in the:

a. north.

b. south.

c. east.

d. west.


61

59. (1 point) Coho Salmon is a fish found in the freshwater streams of North

America. The males of this species have two reproductive strategies to

fertilize the eggs laid by females. Larger males are able to fight with each

other successfully but smaller males are unable to do so. The latter adopt

another strategy, that of sneaking, in which they hide behind rocks and

quickly approach females to fertilize the eggs before the larger males are able

to do so. Which of the following graphs depicts the correct strategies?

Ma

le b

od

y s

ize Fighting

Sneaking

Proximity to female

a. P

roxim

ity t

o f

em

ale

Sneaking

Fighting

Male body size

b.

Ma

le b

od

y s

ize Sneaking

Fighting

Proximity to female

c.

Pro

xim

ity t

o f

em

ale

Fighting

Sneaking

Male body size

d.


62

60. (1 point) Young laughing gull chicks peck at the tip of the parent‟s beak which,

in turn, induces the adult gull to regurgitate food. Experiments were

conducted with one-day old and three-day old chicks, the latter being reared

with their parents. These chicks were presented with the following models of

the parent head and the following responses were obtained:

II

Mean number of pecks / 30 sec 0 5 10 15

One-day old

Experienced

Parental

I

III

IV

Model


63

Choose the correct interpretation of the experiment.

a. Pecking behavior is a fixed action pattern where any long pointed object acts

as an equally effective stimulus.

b. The pecking rate of laughing gull chicks increases with age.

c. The response of one-day old chicks is more pronounced when the model is

closer to that of the parent.

d. Act of pecking is an innate behavior while the discriminatory capacity of the

chicks is a result of learning.


64

61. (1 point) While studying the frogs of a certain species in their natural habitat

during the mating season, you observe a chorus of male frogs in which some

individuals are calling while others remain silent. On further observation, you

see the silent frogs are sitting closer to those that are calling.

Which of the following is most likely to explain the behavior of this chorus of

frogs?

a. The individuals who are not calling are staggering their calls with those of the

others and are likely to call later in the season after the latter have finished

mating.

b. The silent frogs are close genetic relatives of the calling individuals and do

not expend valuable energy in calling as the matings that the latter will

receive would provide adequate indirect fitness to them.

c. The silent frogs have evaluated that their calls are inadequate in attracting

females, as compared to those of the calling individuals, and lie in wait to

sneak matings with the females that approach the calling males.

d. The silent frogs do not expend energy in themselves calling as the female

frogs that are attracted to the calls of the others are anyway likely to visually

inspect the closely-spaced males and then choose their mating partners.


65

BIOSYSTEMATICS (2 points)

62. (1 point) Although Echidna lays eggs, it has been classified as a mammal

due to the presence of mammary glands. Which of the following additional

features support its inclusion in the class Mammalia?

I. Hair over parts of the body.

II. Presence of pituitary and thyroid gland.

III. Complete separation of pulmonary and systemic circulation in a 4 -

chambered heart.

IV. A diaphragm separating thoracic and abdominal cavities.

V. Regulation of body temperature irrespective of ambient temperature.

VI. Enucleated red blood cells.

a. III and VI

b. I, IV and V

c. Only I and IV

d. I and II

e. I, IV and VI

Echidna


66

63. (1 point) Study the adjoining schematically drawn evolutionary lineage. The

derived characters A, B and C represent, respectively:

a. vertebral column and cranium, jaw, lung.

b. tail, heart, teeth.

c. heart, gill, cranium.

d. cranium, cloaca, hepatic portal system.

*************** END OF PART A ***************

Am

ph

ibia

Pro

tocho

rda

ta

Ag

nath

a

Pis

ces

Re

ptilia

Ave

s

Ma

mm

alia

Inve

rteb

rate

s

A B

TIME

C

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